summaryrefslogtreecommitdiff
path: root/drivers/net/ethernet/sun/sunvnet.c
blob: 45c408ef67d0d904e08732c6c2b4f119a8b98ddd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
/* sunvnet.c: Sun LDOM Virtual Network Driver.
 *
 * Copyright (C) 2007, 2008 David S. Miller <davem@davemloft.net>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/ethtool.h>
#include <linux/etherdevice.h>
#include <linux/mutex.h>
#include <linux/highmem.h>
#include <linux/if_vlan.h>

#if IS_ENABLED(CONFIG_IPV6)
#include <linux/icmpv6.h>
#endif

#include <net/ip.h>
#include <net/icmp.h>
#include <net/route.h>

#include <asm/vio.h>
#include <asm/ldc.h>

#include "sunvnet.h"

#define DRV_MODULE_NAME		"sunvnet"
#define DRV_MODULE_VERSION	"1.0"
#define DRV_MODULE_RELDATE	"June 25, 2007"

static char version[] =
	DRV_MODULE_NAME ".c:v" DRV_MODULE_VERSION " (" DRV_MODULE_RELDATE ")\n";
MODULE_AUTHOR("David S. Miller (davem@davemloft.net)");
MODULE_DESCRIPTION("Sun LDOM virtual network driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_MODULE_VERSION);

#define	VNET_MAX_TXQS		16

/* Heuristic for the number of times to exponentially backoff and
 * retry sending an LDC trigger when EAGAIN is encountered
 */
#define	VNET_MAX_RETRIES	10

static int __vnet_tx_trigger(struct vnet_port *port, u32 start);

/* Ordered from largest major to lowest */
static struct vio_version vnet_versions[] = {
	{ .major = 1, .minor = 8 },
	{ .major = 1, .minor = 7 },
	{ .major = 1, .minor = 6 },
	{ .major = 1, .minor = 0 },
};

static inline u32 vnet_tx_dring_avail(struct vio_dring_state *dr)
{
	return vio_dring_avail(dr, VNET_TX_RING_SIZE);
}

static int vnet_handle_unknown(struct vnet_port *port, void *arg)
{
	struct vio_msg_tag *pkt = arg;

	pr_err("Received unknown msg [%02x:%02x:%04x:%08x]\n",
	       pkt->type, pkt->stype, pkt->stype_env, pkt->sid);
	pr_err("Resetting connection\n");

	ldc_disconnect(port->vio.lp);

	return -ECONNRESET;
}

static int vnet_port_alloc_tx_ring(struct vnet_port *port);

static int vnet_send_attr(struct vio_driver_state *vio)
{
	struct vnet_port *port = to_vnet_port(vio);
	struct net_device *dev = port->vp->dev;
	struct vio_net_attr_info pkt;
	int framelen = ETH_FRAME_LEN;
	int i, err;

	err = vnet_port_alloc_tx_ring(to_vnet_port(vio));
	if (err)
		return err;

	memset(&pkt, 0, sizeof(pkt));
	pkt.tag.type = VIO_TYPE_CTRL;
	pkt.tag.stype = VIO_SUBTYPE_INFO;
	pkt.tag.stype_env = VIO_ATTR_INFO;
	pkt.tag.sid = vio_send_sid(vio);
	if (vio_version_before(vio, 1, 2))
		pkt.xfer_mode = VIO_DRING_MODE;
	else
		pkt.xfer_mode = VIO_NEW_DRING_MODE;
	pkt.addr_type = VNET_ADDR_ETHERMAC;
	pkt.ack_freq = 0;
	for (i = 0; i < 6; i++)
		pkt.addr |= (u64)dev->dev_addr[i] << ((5 - i) * 8);
	if (vio_version_after(vio, 1, 3)) {
		if (port->rmtu) {
			port->rmtu = min(VNET_MAXPACKET, port->rmtu);
			pkt.mtu = port->rmtu;
		} else {
			port->rmtu = VNET_MAXPACKET;
			pkt.mtu = port->rmtu;
		}
		if (vio_version_after_eq(vio, 1, 6))
			pkt.options = VIO_TX_DRING;
	} else if (vio_version_before(vio, 1, 3)) {
		pkt.mtu = framelen;
	} else { /* v1.3 */
		pkt.mtu = framelen + VLAN_HLEN;
	}

	pkt.cflags = 0;
	if (vio_version_after_eq(vio, 1, 7) && port->tso) {
		pkt.cflags |= VNET_LSO_IPV4_CAPAB;
		if (!port->tsolen)
			port->tsolen = VNET_MAXTSO;
		pkt.ipv4_lso_maxlen = port->tsolen;
	}

	pkt.plnk_updt = PHYSLINK_UPDATE_NONE;

	viodbg(HS, "SEND NET ATTR xmode[0x%x] atype[0x%x] addr[%llx] "
	       "ackfreq[%u] plnk_updt[0x%02x] opts[0x%02x] mtu[%llu] "
	       "cflags[0x%04x] lso_max[%u]\n",
	       pkt.xfer_mode, pkt.addr_type,
	       (unsigned long long)pkt.addr,
	       pkt.ack_freq, pkt.plnk_updt, pkt.options,
	       (unsigned long long)pkt.mtu, pkt.cflags, pkt.ipv4_lso_maxlen);


	return vio_ldc_send(vio, &pkt, sizeof(pkt));
}

static int handle_attr_info(struct vio_driver_state *vio,
			    struct vio_net_attr_info *pkt)
{
	struct vnet_port *port = to_vnet_port(vio);
	u64	localmtu;
	u8	xfer_mode;

	viodbg(HS, "GOT NET ATTR xmode[0x%x] atype[0x%x] addr[%llx] "
	       "ackfreq[%u] plnk_updt[0x%02x] opts[0x%02x] mtu[%llu] "
	       " (rmtu[%llu]) cflags[0x%04x] lso_max[%u]\n",
	       pkt->xfer_mode, pkt->addr_type,
	       (unsigned long long)pkt->addr,
	       pkt->ack_freq, pkt->plnk_updt, pkt->options,
	       (unsigned long long)pkt->mtu, port->rmtu, pkt->cflags,
	       pkt->ipv4_lso_maxlen);

	pkt->tag.sid = vio_send_sid(vio);

	xfer_mode = pkt->xfer_mode;
	/* for version < 1.2, VIO_DRING_MODE = 0x3 and no bitmask */
	if (vio_version_before(vio, 1, 2) && xfer_mode == VIO_DRING_MODE)
		xfer_mode = VIO_NEW_DRING_MODE;

	/* MTU negotiation:
	 *	< v1.3 - ETH_FRAME_LEN exactly
	 *	> v1.3 - MIN(pkt.mtu, VNET_MAXPACKET, port->rmtu) and change
	 *			pkt->mtu for ACK
	 *	= v1.3 - ETH_FRAME_LEN + VLAN_HLEN exactly
	 */
	if (vio_version_before(vio, 1, 3)) {
		localmtu = ETH_FRAME_LEN;
	} else if (vio_version_after(vio, 1, 3)) {
		localmtu = port->rmtu ? port->rmtu : VNET_MAXPACKET;
		localmtu = min(pkt->mtu, localmtu);
		pkt->mtu = localmtu;
	} else { /* v1.3 */
		localmtu = ETH_FRAME_LEN + VLAN_HLEN;
	}
	port->rmtu = localmtu;

	/* LSO negotiation */
	if (vio_version_after_eq(vio, 1, 7))
		port->tso &= !!(pkt->cflags & VNET_LSO_IPV4_CAPAB);
	else
		port->tso = false;
	if (port->tso) {
		if (!port->tsolen)
			port->tsolen = VNET_MAXTSO;
		port->tsolen = min(port->tsolen, pkt->ipv4_lso_maxlen);
		if (port->tsolen < VNET_MINTSO) {
			port->tso = false;
			port->tsolen = 0;
			pkt->cflags &= ~VNET_LSO_IPV4_CAPAB;
		}
		pkt->ipv4_lso_maxlen = port->tsolen;
	} else {
		pkt->cflags &= ~VNET_LSO_IPV4_CAPAB;
		pkt->ipv4_lso_maxlen = 0;
	}

	/* for version >= 1.6, ACK packet mode we support */
	if (vio_version_after_eq(vio, 1, 6)) {
		pkt->xfer_mode = VIO_NEW_DRING_MODE;
		pkt->options = VIO_TX_DRING;
	}

	if (!(xfer_mode | VIO_NEW_DRING_MODE) ||
	    pkt->addr_type != VNET_ADDR_ETHERMAC ||
	    pkt->mtu != localmtu) {
		viodbg(HS, "SEND NET ATTR NACK\n");

		pkt->tag.stype = VIO_SUBTYPE_NACK;

		(void) vio_ldc_send(vio, pkt, sizeof(*pkt));

		return -ECONNRESET;
	} else {
		viodbg(HS, "SEND NET ATTR ACK xmode[0x%x] atype[0x%x] "
		       "addr[%llx] ackfreq[%u] plnk_updt[0x%02x] opts[0x%02x] "
		       "mtu[%llu] (rmtu[%llu]) cflags[0x%04x] lso_max[%u]\n",
		       pkt->xfer_mode, pkt->addr_type,
		       (unsigned long long)pkt->addr,
		       pkt->ack_freq, pkt->plnk_updt, pkt->options,
		       (unsigned long long)pkt->mtu, port->rmtu, pkt->cflags,
		       pkt->ipv4_lso_maxlen);

		pkt->tag.stype = VIO_SUBTYPE_ACK;

		return vio_ldc_send(vio, pkt, sizeof(*pkt));
	}

}

static int handle_attr_ack(struct vio_driver_state *vio,
			   struct vio_net_attr_info *pkt)
{
	viodbg(HS, "GOT NET ATTR ACK\n");

	return 0;
}

static int handle_attr_nack(struct vio_driver_state *vio,
			    struct vio_net_attr_info *pkt)
{
	viodbg(HS, "GOT NET ATTR NACK\n");

	return -ECONNRESET;
}

static int vnet_handle_attr(struct vio_driver_state *vio, void *arg)
{
	struct vio_net_attr_info *pkt = arg;

	switch (pkt->tag.stype) {
	case VIO_SUBTYPE_INFO:
		return handle_attr_info(vio, pkt);

	case VIO_SUBTYPE_ACK:
		return handle_attr_ack(vio, pkt);

	case VIO_SUBTYPE_NACK:
		return handle_attr_nack(vio, pkt);

	default:
		return -ECONNRESET;
	}
}

static void vnet_handshake_complete(struct vio_driver_state *vio)
{
	struct vio_dring_state *dr;

	dr = &vio->drings[VIO_DRIVER_RX_RING];
	dr->snd_nxt = dr->rcv_nxt = 1;

	dr = &vio->drings[VIO_DRIVER_TX_RING];
	dr->snd_nxt = dr->rcv_nxt = 1;
}

/* The hypervisor interface that implements copying to/from imported
 * memory from another domain requires that copies are done to 8-byte
 * aligned buffers, and that the lengths of such copies are also 8-byte
 * multiples.
 *
 * So we align skb->data to an 8-byte multiple and pad-out the data
 * area so we can round the copy length up to the next multiple of
 * 8 for the copy.
 *
 * The transmitter puts the actual start of the packet 6 bytes into
 * the buffer it sends over, so that the IP headers after the ethernet
 * header are aligned properly.  These 6 bytes are not in the descriptor
 * length, they are simply implied.  This offset is represented using
 * the VNET_PACKET_SKIP macro.
 */
static struct sk_buff *alloc_and_align_skb(struct net_device *dev,
					   unsigned int len)
{
	struct sk_buff *skb = netdev_alloc_skb(dev, len+VNET_PACKET_SKIP+8+8);
	unsigned long addr, off;

	if (unlikely(!skb))
		return NULL;

	addr = (unsigned long) skb->data;
	off = ((addr + 7UL) & ~7UL) - addr;
	if (off)
		skb_reserve(skb, off);

	return skb;
}

static inline void vnet_fullcsum(struct sk_buff *skb)
{
	struct iphdr *iph = ip_hdr(skb);
	int offset = skb_transport_offset(skb);

	if (skb->protocol != htons(ETH_P_IP))
		return;
	if (iph->protocol != IPPROTO_TCP &&
	    iph->protocol != IPPROTO_UDP)
		return;
	skb->ip_summed = CHECKSUM_NONE;
	skb->csum_level = 1;
	skb->csum = 0;
	if (iph->protocol == IPPROTO_TCP) {
		struct tcphdr *ptcp = tcp_hdr(skb);

		ptcp->check = 0;
		skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
		ptcp->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
						skb->len - offset, IPPROTO_TCP,
						skb->csum);
	} else if (iph->protocol == IPPROTO_UDP) {
		struct udphdr *pudp = udp_hdr(skb);

		pudp->check = 0;
		skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
		pudp->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
						skb->len - offset, IPPROTO_UDP,
						skb->csum);
	}
}

static int vnet_rx_one(struct vnet_port *port, struct vio_net_desc *desc)
{
	struct net_device *dev = port->vp->dev;
	unsigned int len = desc->size;
	unsigned int copy_len;
	struct sk_buff *skb;
	int err;

	err = -EMSGSIZE;
	if (unlikely(len < ETH_ZLEN || len > port->rmtu)) {
		dev->stats.rx_length_errors++;
		goto out_dropped;
	}

	skb = alloc_and_align_skb(dev, len);
	err = -ENOMEM;
	if (unlikely(!skb)) {
		dev->stats.rx_missed_errors++;
		goto out_dropped;
	}

	copy_len = (len + VNET_PACKET_SKIP + 7U) & ~7U;
	skb_put(skb, copy_len);
	err = ldc_copy(port->vio.lp, LDC_COPY_IN,
		       skb->data, copy_len, 0,
		       desc->cookies, desc->ncookies);
	if (unlikely(err < 0)) {
		dev->stats.rx_frame_errors++;
		goto out_free_skb;
	}

	skb_pull(skb, VNET_PACKET_SKIP);
	skb_trim(skb, len);
	skb->protocol = eth_type_trans(skb, dev);

	if (vio_version_after_eq(&port->vio, 1, 8)) {
		struct vio_net_dext *dext = vio_net_ext(desc);

		if (dext->flags & VNET_PKT_HCK_IPV4_HDRCKSUM) {
			if (skb->protocol == ETH_P_IP) {
				struct iphdr *iph = (struct iphdr *)skb->data;

				iph->check = 0;
				ip_send_check(iph);
			}
		}
		if ((dext->flags & VNET_PKT_HCK_FULLCKSUM) &&
		    skb->ip_summed == CHECKSUM_NONE)
			vnet_fullcsum(skb);
		if (dext->flags & VNET_PKT_HCK_IPV4_HDRCKSUM_OK) {
			skb->ip_summed = CHECKSUM_PARTIAL;
			skb->csum_level = 0;
			if (dext->flags & VNET_PKT_HCK_FULLCKSUM_OK)
				skb->csum_level = 1;
		}
	}

	skb->ip_summed = port->switch_port ? CHECKSUM_NONE : CHECKSUM_PARTIAL;

	dev->stats.rx_packets++;
	dev->stats.rx_bytes += len;
	napi_gro_receive(&port->napi, skb);
	return 0;

out_free_skb:
	kfree_skb(skb);

out_dropped:
	dev->stats.rx_dropped++;
	return err;
}

static int vnet_send_ack(struct vnet_port *port, struct vio_dring_state *dr,
			 u32 start, u32 end, u8 vio_dring_state)
{
	struct vio_dring_data hdr = {
		.tag = {
			.type		= VIO_TYPE_DATA,
			.stype		= VIO_SUBTYPE_ACK,
			.stype_env	= VIO_DRING_DATA,
			.sid		= vio_send_sid(&port->vio),
		},
		.dring_ident		= dr->ident,
		.start_idx		= start,
		.end_idx		= end,
		.state			= vio_dring_state,
	};
	int err, delay;
	int retries = 0;

	hdr.seq = dr->snd_nxt;
	delay = 1;
	do {
		err = vio_ldc_send(&port->vio, &hdr, sizeof(hdr));
		if (err > 0) {
			dr->snd_nxt++;
			break;
		}
		udelay(delay);
		if ((delay <<= 1) > 128)
			delay = 128;
		if (retries++ > VNET_MAX_RETRIES) {
			pr_info("ECONNRESET %x:%x:%x:%x:%x:%x\n",
				port->raddr[0], port->raddr[1],
				port->raddr[2], port->raddr[3],
				port->raddr[4], port->raddr[5]);
			break;
		}
	} while (err == -EAGAIN);

	if (err <= 0 && vio_dring_state == VIO_DRING_STOPPED) {
		port->stop_rx_idx = end;
		port->stop_rx = true;
	} else {
		port->stop_rx_idx = 0;
		port->stop_rx = false;
	}

	return err;
}

static struct vio_net_desc *get_rx_desc(struct vnet_port *port,
					struct vio_dring_state *dr,
					u32 index)
{
	struct vio_net_desc *desc = port->vio.desc_buf;
	int err;

	err = ldc_get_dring_entry(port->vio.lp, desc, dr->entry_size,
				  (index * dr->entry_size),
				  dr->cookies, dr->ncookies);
	if (err < 0)
		return ERR_PTR(err);

	return desc;
}

static int put_rx_desc(struct vnet_port *port,
		       struct vio_dring_state *dr,
		       struct vio_net_desc *desc,
		       u32 index)
{
	int err;

	err = ldc_put_dring_entry(port->vio.lp, desc, dr->entry_size,
				  (index * dr->entry_size),
				  dr->cookies, dr->ncookies);
	if (err < 0)
		return err;

	return 0;
}

static int vnet_walk_rx_one(struct vnet_port *port,
			    struct vio_dring_state *dr,
			    u32 index, int *needs_ack)
{
	struct vio_net_desc *desc = get_rx_desc(port, dr, index);
	struct vio_driver_state *vio = &port->vio;
	int err;

	BUG_ON(desc == NULL);
	if (IS_ERR(desc))
		return PTR_ERR(desc);

	if (desc->hdr.state != VIO_DESC_READY)
		return 1;

	rmb();

	viodbg(DATA, "vio_walk_rx_one desc[%02x:%02x:%08x:%08x:%llx:%llx]\n",
	       desc->hdr.state, desc->hdr.ack,
	       desc->size, desc->ncookies,
	       desc->cookies[0].cookie_addr,
	       desc->cookies[0].cookie_size);

	err = vnet_rx_one(port, desc);
	if (err == -ECONNRESET)
		return err;
	desc->hdr.state = VIO_DESC_DONE;
	err = put_rx_desc(port, dr, desc, index);
	if (err < 0)
		return err;
	*needs_ack = desc->hdr.ack;
	return 0;
}

static int vnet_walk_rx(struct vnet_port *port, struct vio_dring_state *dr,
			u32 start, u32 end, int *npkts, int budget)
{
	struct vio_driver_state *vio = &port->vio;
	int ack_start = -1, ack_end = -1;
	bool send_ack = true;

	end = (end == (u32) -1) ? vio_dring_prev(dr, start)
				: vio_dring_next(dr, end);

	viodbg(DATA, "vnet_walk_rx start[%08x] end[%08x]\n", start, end);

	while (start != end) {
		int ack = 0, err = vnet_walk_rx_one(port, dr, start, &ack);
		if (err == -ECONNRESET)
			return err;
		if (err != 0)
			break;
		(*npkts)++;
		if (ack_start == -1)
			ack_start = start;
		ack_end = start;
		start = vio_dring_next(dr, start);
		if (ack && start != end) {
			err = vnet_send_ack(port, dr, ack_start, ack_end,
					    VIO_DRING_ACTIVE);
			if (err == -ECONNRESET)
				return err;
			ack_start = -1;
		}
		if ((*npkts) >= budget) {
			send_ack = false;
			break;
		}
	}
	if (unlikely(ack_start == -1))
		ack_start = ack_end = vio_dring_prev(dr, start);
	if (send_ack) {
		port->napi_resume = false;
		return vnet_send_ack(port, dr, ack_start, ack_end,
				     VIO_DRING_STOPPED);
	} else  {
		port->napi_resume = true;
		port->napi_stop_idx = ack_end;
		return 1;
	}
}

static int vnet_rx(struct vnet_port *port, void *msgbuf, int *npkts,
		   int budget)
{
	struct vio_dring_data *pkt = msgbuf;
	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_RX_RING];
	struct vio_driver_state *vio = &port->vio;

	viodbg(DATA, "vnet_rx stype_env[%04x] seq[%016llx] rcv_nxt[%016llx]\n",
	       pkt->tag.stype_env, pkt->seq, dr->rcv_nxt);

	if (unlikely(pkt->tag.stype_env != VIO_DRING_DATA))
		return 0;
	if (unlikely(pkt->seq != dr->rcv_nxt)) {
		pr_err("RX out of sequence seq[0x%llx] rcv_nxt[0x%llx]\n",
		       pkt->seq, dr->rcv_nxt);
		return 0;
	}

	if (!port->napi_resume)
		dr->rcv_nxt++;

	/* XXX Validate pkt->start_idx and pkt->end_idx XXX */

	return vnet_walk_rx(port, dr, pkt->start_idx, pkt->end_idx,
			    npkts, budget);
}

static int idx_is_pending(struct vio_dring_state *dr, u32 end)
{
	u32 idx = dr->cons;
	int found = 0;

	while (idx != dr->prod) {
		if (idx == end) {
			found = 1;
			break;
		}
		idx = vio_dring_next(dr, idx);
	}
	return found;
}

static int vnet_ack(struct vnet_port *port, void *msgbuf)
{
	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];
	struct vio_dring_data *pkt = msgbuf;
	struct net_device *dev;
	struct vnet *vp;
	u32 end;
	struct vio_net_desc *desc;
	struct netdev_queue *txq;

	if (unlikely(pkt->tag.stype_env != VIO_DRING_DATA))
		return 0;

	end = pkt->end_idx;
	vp = port->vp;
	dev = vp->dev;
	netif_tx_lock(dev);
	if (unlikely(!idx_is_pending(dr, end))) {
		netif_tx_unlock(dev);
		return 0;
	}

	/* sync for race conditions with vnet_start_xmit() and tell xmit it
	 * is time to send a trigger.
	 */
	dr->cons = vio_dring_next(dr, end);
	desc = vio_dring_entry(dr, dr->cons);
	if (desc->hdr.state == VIO_DESC_READY && !port->start_cons) {
		/* vnet_start_xmit() just populated this dring but missed
		 * sending the "start" LDC message to the consumer.
		 * Send a "start" trigger on its behalf.
		 */
		if (__vnet_tx_trigger(port, dr->cons) > 0)
			port->start_cons = false;
		else
			port->start_cons = true;
	} else {
		port->start_cons = true;
	}
	netif_tx_unlock(dev);

	txq = netdev_get_tx_queue(dev, port->q_index);
	if (unlikely(netif_tx_queue_stopped(txq) &&
		     vnet_tx_dring_avail(dr) >= VNET_TX_WAKEUP_THRESH(dr)))
		return 1;

	return 0;
}

static int vnet_nack(struct vnet_port *port, void *msgbuf)
{
	/* XXX just reset or similar XXX */
	return 0;
}

static int handle_mcast(struct vnet_port *port, void *msgbuf)
{
	struct vio_net_mcast_info *pkt = msgbuf;

	if (pkt->tag.stype != VIO_SUBTYPE_ACK)
		pr_err("%s: Got unexpected MCAST reply [%02x:%02x:%04x:%08x]\n",
		       port->vp->dev->name,
		       pkt->tag.type,
		       pkt->tag.stype,
		       pkt->tag.stype_env,
		       pkt->tag.sid);

	return 0;
}

/* Got back a STOPPED LDC message on port. If the queue is stopped,
 * wake it up so that we'll send out another START message at the
 * next TX.
 */
static void maybe_tx_wakeup(struct vnet_port *port)
{
	struct netdev_queue *txq;

	txq = netdev_get_tx_queue(port->vp->dev, port->q_index);
	__netif_tx_lock(txq, smp_processor_id());
	if (likely(netif_tx_queue_stopped(txq))) {
		struct vio_dring_state *dr;

		dr = &port->vio.drings[VIO_DRIVER_TX_RING];
		netif_tx_wake_queue(txq);
	}
	__netif_tx_unlock(txq);
}

static inline bool port_is_up(struct vnet_port *vnet)
{
	struct vio_driver_state *vio = &vnet->vio;

	return !!(vio->hs_state & VIO_HS_COMPLETE);
}

static int vnet_event_napi(struct vnet_port *port, int budget)
{
	struct vio_driver_state *vio = &port->vio;
	int tx_wakeup, err;
	int npkts = 0;
	int event = (port->rx_event & LDC_EVENT_RESET);

ldc_ctrl:
	if (unlikely(event == LDC_EVENT_RESET ||
		     event == LDC_EVENT_UP)) {
		vio_link_state_change(vio, event);

		if (event == LDC_EVENT_RESET) {
			port->rmtu = 0;
			port->tso = true;
			port->tsolen = 0;
			vio_port_up(vio);
		}
		port->rx_event = 0;
		return 0;
	}
	/* We may have multiple LDC events in rx_event. Unroll send_events() */
	event = (port->rx_event & LDC_EVENT_UP);
	port->rx_event &= ~(LDC_EVENT_RESET|LDC_EVENT_UP);
	if (event == LDC_EVENT_UP)
		goto ldc_ctrl;
	event = port->rx_event;
	if (!(event & LDC_EVENT_DATA_READY))
		return 0;

	/* we dont expect any other bits than RESET, UP, DATA_READY */
	BUG_ON(event != LDC_EVENT_DATA_READY);

	tx_wakeup = err = 0;
	while (1) {
		union {
			struct vio_msg_tag tag;
			u64 raw[8];
		} msgbuf;

		if (port->napi_resume) {
			struct vio_dring_data *pkt =
				(struct vio_dring_data *)&msgbuf;
			struct vio_dring_state *dr =
				&port->vio.drings[VIO_DRIVER_RX_RING];

			pkt->tag.type = VIO_TYPE_DATA;
			pkt->tag.stype = VIO_SUBTYPE_INFO;
			pkt->tag.stype_env = VIO_DRING_DATA;
			pkt->seq = dr->rcv_nxt;
			pkt->start_idx = vio_dring_next(dr, port->napi_stop_idx);
			pkt->end_idx = -1;
			goto napi_resume;
		}
		err = ldc_read(vio->lp, &msgbuf, sizeof(msgbuf));
		if (unlikely(err < 0)) {
			if (err == -ECONNRESET)
				vio_conn_reset(vio);
			break;
		}
		if (err == 0)
			break;
		viodbg(DATA, "TAG [%02x:%02x:%04x:%08x]\n",
		       msgbuf.tag.type,
		       msgbuf.tag.stype,
		       msgbuf.tag.stype_env,
		       msgbuf.tag.sid);
		err = vio_validate_sid(vio, &msgbuf.tag);
		if (err < 0)
			break;
napi_resume:
		if (likely(msgbuf.tag.type == VIO_TYPE_DATA)) {
			if (msgbuf.tag.stype == VIO_SUBTYPE_INFO) {
				if (!port_is_up(port)) {
					/* failures like handshake_failure()
					 * may have cleaned up dring, but
					 * NAPI polling may bring us here.
					 */
					err = -ECONNRESET;
					break;
				}
				err = vnet_rx(port, &msgbuf, &npkts, budget);
				if (npkts >= budget)
					break;
				if (npkts == 0)
					break;
			} else if (msgbuf.tag.stype == VIO_SUBTYPE_ACK) {
				err = vnet_ack(port, &msgbuf);
				if (err > 0)
					tx_wakeup |= err;
			} else if (msgbuf.tag.stype == VIO_SUBTYPE_NACK) {
				err = vnet_nack(port, &msgbuf);
			}
		} else if (msgbuf.tag.type == VIO_TYPE_CTRL) {
			if (msgbuf.tag.stype_env == VNET_MCAST_INFO)
				err = handle_mcast(port, &msgbuf);
			else
				err = vio_control_pkt_engine(vio, &msgbuf);
			if (err)
				break;
		} else {
			err = vnet_handle_unknown(port, &msgbuf);
		}
		if (err == -ECONNRESET)
			break;
	}
	if (unlikely(tx_wakeup && err != -ECONNRESET))
		maybe_tx_wakeup(port);
	return npkts;
}

static int vnet_poll(struct napi_struct *napi, int budget)
{
	struct vnet_port *port = container_of(napi, struct vnet_port, napi);
	struct vio_driver_state *vio = &port->vio;
	int processed = vnet_event_napi(port, budget);

	if (processed < budget) {
		napi_complete(napi);
		port->rx_event &= ~LDC_EVENT_DATA_READY;
		vio_set_intr(vio->vdev->rx_ino, HV_INTR_ENABLED);
	}
	return processed;
}

static void vnet_event(void *arg, int event)
{
	struct vnet_port *port = arg;
	struct vio_driver_state *vio = &port->vio;

	port->rx_event |= event;
	vio_set_intr(vio->vdev->rx_ino, HV_INTR_DISABLED);
	napi_schedule(&port->napi);

}

static int __vnet_tx_trigger(struct vnet_port *port, u32 start)
{
	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];
	struct vio_dring_data hdr = {
		.tag = {
			.type		= VIO_TYPE_DATA,
			.stype		= VIO_SUBTYPE_INFO,
			.stype_env	= VIO_DRING_DATA,
			.sid		= vio_send_sid(&port->vio),
		},
		.dring_ident		= dr->ident,
		.start_idx		= start,
		.end_idx		= (u32) -1,
	};
	int err, delay;
	int retries = 0;

	if (port->stop_rx) {
		err = vnet_send_ack(port,
				    &port->vio.drings[VIO_DRIVER_RX_RING],
				    port->stop_rx_idx, -1,
				    VIO_DRING_STOPPED);
		if (err <= 0)
			return err;
	}

	hdr.seq = dr->snd_nxt;
	delay = 1;
	do {
		err = vio_ldc_send(&port->vio, &hdr, sizeof(hdr));
		if (err > 0) {
			dr->snd_nxt++;
			break;
		}
		udelay(delay);
		if ((delay <<= 1) > 128)
			delay = 128;
		if (retries++ > VNET_MAX_RETRIES)
			break;
	} while (err == -EAGAIN);

	return err;
}

struct vnet_port *__tx_port_find(struct vnet *vp, struct sk_buff *skb)
{
	unsigned int hash = vnet_hashfn(skb->data);
	struct hlist_head *hp = &vp->port_hash[hash];
	struct vnet_port *port;

	hlist_for_each_entry_rcu(port, hp, hash) {
		if (!port_is_up(port))
			continue;
		if (ether_addr_equal(port->raddr, skb->data))
			return port;
	}
	list_for_each_entry_rcu(port, &vp->port_list, list) {
		if (!port->switch_port)
			continue;
		if (!port_is_up(port))
			continue;
		return port;
	}
	return NULL;
}

static struct sk_buff *vnet_clean_tx_ring(struct vnet_port *port,
					  unsigned *pending)
{
	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];
	struct sk_buff *skb = NULL;
	int i, txi;

	*pending = 0;

	txi = dr->prod-1;
	if (txi < 0)
		txi = VNET_TX_RING_SIZE-1;

	for (i = 0; i < VNET_TX_RING_SIZE; ++i) {
		struct vio_net_desc *d;

		d = vio_dring_entry(dr, txi);

		if (d->hdr.state == VIO_DESC_DONE) {
			if (port->tx_bufs[txi].skb) {
				BUG_ON(port->tx_bufs[txi].skb->next);

				port->tx_bufs[txi].skb->next = skb;
				skb = port->tx_bufs[txi].skb;
				port->tx_bufs[txi].skb = NULL;

				ldc_unmap(port->vio.lp,
					  port->tx_bufs[txi].cookies,
					  port->tx_bufs[txi].ncookies);
			}
			d->hdr.state = VIO_DESC_FREE;
		} else if (d->hdr.state == VIO_DESC_READY) {
			(*pending)++;
		} else if (d->hdr.state == VIO_DESC_FREE) {
			break;
		}
		--txi;
		if (txi < 0)
			txi = VNET_TX_RING_SIZE-1;
	}
	return skb;
}

static inline void vnet_free_skbs(struct sk_buff *skb)
{
	struct sk_buff *next;

	while (skb) {
		next = skb->next;
		skb->next = NULL;
		dev_kfree_skb(skb);
		skb = next;
	}
}

static void vnet_clean_timer_expire(unsigned long port0)
{
	struct vnet_port *port = (struct vnet_port *)port0;
	struct sk_buff *freeskbs;
	unsigned pending;

	netif_tx_lock(port->vp->dev);
	freeskbs = vnet_clean_tx_ring(port, &pending);
	netif_tx_unlock(port->vp->dev);

	vnet_free_skbs(freeskbs);

	if (pending)
		(void)mod_timer(&port->clean_timer,
				jiffies + VNET_CLEAN_TIMEOUT);
	 else
		del_timer(&port->clean_timer);
}

static inline int vnet_skb_map(struct ldc_channel *lp, struct sk_buff *skb,
			       struct ldc_trans_cookie *cookies, int ncookies,
			       unsigned int map_perm)
{
	int i, nc, err, blen;

	/* header */
	blen = skb_headlen(skb);
	if (blen < ETH_ZLEN)
		blen = ETH_ZLEN;
	blen += VNET_PACKET_SKIP;
	blen += 8 - (blen & 7);

	err = ldc_map_single(lp, skb->data-VNET_PACKET_SKIP, blen, cookies,
			     ncookies, map_perm);
	if (err < 0)
		return err;
	nc = err;

	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
		skb_frag_t *f = &skb_shinfo(skb)->frags[i];
		u8 *vaddr;

		if (nc < ncookies) {
			vaddr = kmap_atomic(skb_frag_page(f));
			blen = skb_frag_size(f);
			blen += 8 - (blen & 7);
			err = ldc_map_single(lp, vaddr + f->page_offset,
					     blen, cookies + nc, ncookies - nc,
					     map_perm);
			kunmap_atomic(vaddr);
		} else {
			err = -EMSGSIZE;
		}

		if (err < 0) {
			ldc_unmap(lp, cookies, nc);
			return err;
		}
		nc += err;
	}
	return nc;
}

static inline struct sk_buff *vnet_skb_shape(struct sk_buff *skb, int ncookies)
{
	struct sk_buff *nskb;
	int i, len, pad, docopy;

	len = skb->len;
	pad = 0;
	if (len < ETH_ZLEN) {
		pad += ETH_ZLEN - skb->len;
		len += pad;
	}
	len += VNET_PACKET_SKIP;
	pad += 8 - (len & 7);

	/* make sure we have enough cookies and alignment in every frag */
	docopy = skb_shinfo(skb)->nr_frags >= ncookies;
	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
		skb_frag_t *f = &skb_shinfo(skb)->frags[i];

		docopy |= f->page_offset & 7;
	}
	if (((unsigned long)skb->data & 7) != VNET_PACKET_SKIP ||
	    skb_tailroom(skb) < pad ||
	    skb_headroom(skb) < VNET_PACKET_SKIP || docopy) {
		int start = 0, offset;
		__wsum csum;

		len = skb->len > ETH_ZLEN ? skb->len : ETH_ZLEN;
		nskb = alloc_and_align_skb(skb->dev, len);
		if (nskb == NULL) {
			dev_kfree_skb(skb);
			return NULL;
		}
		skb_reserve(nskb, VNET_PACKET_SKIP);

		nskb->protocol = skb->protocol;
		offset = skb_mac_header(skb) - skb->data;
		skb_set_mac_header(nskb, offset);
		offset = skb_network_header(skb) - skb->data;
		skb_set_network_header(nskb, offset);
		offset = skb_transport_header(skb) - skb->data;
		skb_set_transport_header(nskb, offset);

		offset = 0;
		nskb->csum_offset = skb->csum_offset;
		nskb->ip_summed = skb->ip_summed;

		if (skb->ip_summed == CHECKSUM_PARTIAL)
			start = skb_checksum_start_offset(skb);
		if (start) {
			struct iphdr *iph = ip_hdr(nskb);
			int offset = start + nskb->csum_offset;

			if (skb_copy_bits(skb, 0, nskb->data, start)) {
				dev_kfree_skb(nskb);
				dev_kfree_skb(skb);
				return NULL;
			}
			*(__sum16 *)(skb->data + offset) = 0;
			csum = skb_copy_and_csum_bits(skb, start,
						      nskb->data + start,
						      skb->len - start, 0);
			if (iph->protocol == IPPROTO_TCP ||
			    iph->protocol == IPPROTO_UDP) {
				csum = csum_tcpudp_magic(iph->saddr, iph->daddr,
							 skb->len - start,
							 iph->protocol, csum);
			}
			*(__sum16 *)(nskb->data + offset) = csum;

			nskb->ip_summed = CHECKSUM_NONE;
		} else if (skb_copy_bits(skb, 0, nskb->data, skb->len)) {
			dev_kfree_skb(nskb);
			dev_kfree_skb(skb);
			return NULL;
		}
		(void)skb_put(nskb, skb->len);
		if (skb_is_gso(skb)) {
			skb_shinfo(nskb)->gso_size = skb_shinfo(skb)->gso_size;
			skb_shinfo(nskb)->gso_type = skb_shinfo(skb)->gso_type;
		}
		dev_kfree_skb(skb);
		skb = nskb;
	}
	return skb;
}

static u16
vnet_select_queue(struct net_device *dev, struct sk_buff *skb,
		  void *accel_priv, select_queue_fallback_t fallback)
{
	struct vnet *vp = netdev_priv(dev);
	struct vnet_port *port = __tx_port_find(vp, skb);

	if (port == NULL)
		return 0;
	return port->q_index;
}

static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev);

static int vnet_handle_offloads(struct vnet_port *port, struct sk_buff *skb)
{
	struct net_device *dev = port->vp->dev;
	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];
	struct sk_buff *segs;
	int maclen, datalen;
	int status;
	int gso_size, gso_type, gso_segs;
	int hlen = skb_transport_header(skb) - skb_mac_header(skb);
	int proto = IPPROTO_IP;

	if (skb->protocol == htons(ETH_P_IP))
		proto = ip_hdr(skb)->protocol;
	else if (skb->protocol == htons(ETH_P_IPV6))
		proto = ipv6_hdr(skb)->nexthdr;

	if (proto == IPPROTO_TCP)
		hlen += tcp_hdr(skb)->doff * 4;
	else if (proto == IPPROTO_UDP)
		hlen += sizeof(struct udphdr);
	else {
		pr_err("vnet_handle_offloads GSO with unknown transport "
		       "protocol %d tproto %d\n", skb->protocol, proto);
		hlen = 128; /* XXX */
	}
	datalen = port->tsolen - hlen;

	gso_size = skb_shinfo(skb)->gso_size;
	gso_type = skb_shinfo(skb)->gso_type;
	gso_segs = skb_shinfo(skb)->gso_segs;

	if (port->tso && gso_size < datalen)
		gso_segs = DIV_ROUND_UP(skb->len - hlen, datalen);

	if (unlikely(vnet_tx_dring_avail(dr) < gso_segs)) {
		struct netdev_queue *txq;

		txq  = netdev_get_tx_queue(dev, port->q_index);
		netif_tx_stop_queue(txq);
		if (vnet_tx_dring_avail(dr) < skb_shinfo(skb)->gso_segs)
			return NETDEV_TX_BUSY;
		netif_tx_wake_queue(txq);
	}

	maclen = skb_network_header(skb) - skb_mac_header(skb);
	skb_pull(skb, maclen);

	if (port->tso && gso_size < datalen) {
		/* segment to TSO size */
		skb_shinfo(skb)->gso_size = datalen;
		skb_shinfo(skb)->gso_segs = gso_segs;

		segs = skb_gso_segment(skb, dev->features & ~NETIF_F_TSO);

		/* restore gso_size & gso_segs */
		skb_shinfo(skb)->gso_size = gso_size;
		skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len - hlen,
							 gso_size);
	} else
		segs = skb_gso_segment(skb, dev->features & ~NETIF_F_TSO);
	if (IS_ERR(segs)) {
		dev->stats.tx_dropped++;
		return NETDEV_TX_OK;
	}

	skb_push(skb, maclen);
	skb_reset_mac_header(skb);

	status = 0;
	while (segs) {
		struct sk_buff *curr = segs;

		segs = segs->next;
		curr->next = NULL;
		if (port->tso && curr->len > dev->mtu) {
			skb_shinfo(curr)->gso_size = gso_size;
			skb_shinfo(curr)->gso_type = gso_type;
			skb_shinfo(curr)->gso_segs =
				DIV_ROUND_UP(curr->len - hlen, gso_size);
		} else
			skb_shinfo(curr)->gso_size = 0;

		skb_push(curr, maclen);
		skb_reset_mac_header(curr);
		memcpy(skb_mac_header(curr), skb_mac_header(skb),
		       maclen);
		curr->csum_start = skb_transport_header(curr) - curr->head;
		if (ip_hdr(curr)->protocol == IPPROTO_TCP)
			curr->csum_offset = offsetof(struct tcphdr, check);
		else if (ip_hdr(curr)->protocol == IPPROTO_UDP)
			curr->csum_offset = offsetof(struct udphdr, check);

		if (!(status & NETDEV_TX_MASK))
			status = vnet_start_xmit(curr, dev);
		if (status & NETDEV_TX_MASK)
			dev_kfree_skb_any(curr);
	}

	if (!(status & NETDEV_TX_MASK))
		dev_kfree_skb_any(skb);
	return status;
}

static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct vnet *vp = netdev_priv(dev);
	struct vnet_port *port = NULL;
	struct vio_dring_state *dr;
	struct vio_net_desc *d;
	unsigned int len;
	struct sk_buff *freeskbs = NULL;
	int i, err, txi;
	unsigned pending = 0;
	struct netdev_queue *txq;

	rcu_read_lock();
	port = __tx_port_find(vp, skb);
	if (unlikely(!port)) {
		rcu_read_unlock();
		goto out_dropped;
	}

	if (skb_is_gso(skb) && skb->len > port->tsolen) {
		err = vnet_handle_offloads(port, skb);
		rcu_read_unlock();
		return err;
	}

	if (!skb_is_gso(skb) && skb->len > port->rmtu) {
		unsigned long localmtu = port->rmtu - ETH_HLEN;

		if (vio_version_after_eq(&port->vio, 1, 3))
			localmtu -= VLAN_HLEN;

		if (skb->protocol == htons(ETH_P_IP)) {
			struct flowi4 fl4;
			struct rtable *rt = NULL;

			memset(&fl4, 0, sizeof(fl4));
			fl4.flowi4_oif = dev->ifindex;
			fl4.flowi4_tos = RT_TOS(ip_hdr(skb)->tos);
			fl4.daddr = ip_hdr(skb)->daddr;
			fl4.saddr = ip_hdr(skb)->saddr;

			rt = ip_route_output_key(dev_net(dev), &fl4);
			rcu_read_unlock();
			if (!IS_ERR(rt)) {
				skb_dst_set(skb, &rt->dst);
				icmp_send(skb, ICMP_DEST_UNREACH,
					  ICMP_FRAG_NEEDED,
					  htonl(localmtu));
			}
		}
#if IS_ENABLED(CONFIG_IPV6)
		else if (skb->protocol == htons(ETH_P_IPV6))
			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, localmtu);
#endif
		goto out_dropped;
	}

	skb = vnet_skb_shape(skb, 2);

	if (unlikely(!skb))
		goto out_dropped;

	if (skb->ip_summed == CHECKSUM_PARTIAL)
		vnet_fullcsum(skb);

	dr = &port->vio.drings[VIO_DRIVER_TX_RING];
	i = skb_get_queue_mapping(skb);
	txq = netdev_get_tx_queue(dev, i);
	if (unlikely(vnet_tx_dring_avail(dr) < 1)) {
		if (!netif_tx_queue_stopped(txq)) {
			netif_tx_stop_queue(txq);

			/* This is a hard error, log it. */
			netdev_err(dev, "BUG! Tx Ring full when queue awake!\n");
			dev->stats.tx_errors++;
		}
		rcu_read_unlock();
		return NETDEV_TX_BUSY;
	}

	d = vio_dring_cur(dr);

	txi = dr->prod;

	freeskbs = vnet_clean_tx_ring(port, &pending);

	BUG_ON(port->tx_bufs[txi].skb);

	len = skb->len;
	if (len < ETH_ZLEN)
		len = ETH_ZLEN;

	err = vnet_skb_map(port->vio.lp, skb, port->tx_bufs[txi].cookies, 2,
			   (LDC_MAP_SHADOW | LDC_MAP_DIRECT | LDC_MAP_RW));
	if (err < 0) {
		netdev_info(dev, "tx buffer map error %d\n", err);
		goto out_dropped;
	}

	port->tx_bufs[txi].skb = skb;
	skb = NULL;
	port->tx_bufs[txi].ncookies = err;

	/* We don't rely on the ACKs to free the skb in vnet_start_xmit(),
	 * thus it is safe to not set VIO_ACK_ENABLE for each transmission:
	 * the protocol itself does not require it as long as the peer
	 * sends a VIO_SUBTYPE_ACK for VIO_DRING_STOPPED.
	 *
	 * An ACK for every packet in the ring is expensive as the
	 * sending of LDC messages is slow and affects performance.
	 */
	d->hdr.ack = VIO_ACK_DISABLE;
	d->size = len;
	d->ncookies = port->tx_bufs[txi].ncookies;
	for (i = 0; i < d->ncookies; i++)
		d->cookies[i] = port->tx_bufs[txi].cookies[i];
	if (vio_version_after_eq(&port->vio, 1, 7)) {
		struct vio_net_dext *dext = vio_net_ext(d);

		memset(dext, 0, sizeof(*dext));
		if (skb_is_gso(port->tx_bufs[txi].skb)) {
			dext->ipv4_lso_mss = skb_shinfo(port->tx_bufs[txi].skb)
					     ->gso_size;
			dext->flags |= VNET_PKT_IPV4_LSO;
		}
		if (vio_version_after_eq(&port->vio, 1, 8) &&
		    !port->switch_port) {
			dext->flags |= VNET_PKT_HCK_IPV4_HDRCKSUM_OK;
			dext->flags |= VNET_PKT_HCK_FULLCKSUM_OK;
		}
	}

	/* This has to be a non-SMP write barrier because we are writing
	 * to memory which is shared with the peer LDOM.
	 */
	wmb();

	d->hdr.state = VIO_DESC_READY;

	/* Exactly one ldc "start" trigger (for dr->cons) needs to be sent
	 * to notify the consumer that some descriptors are READY.
	 * After that "start" trigger, no additional triggers are needed until
	 * a DRING_STOPPED is received from the consumer. The dr->cons field
	 * (set up by vnet_ack()) has the value of the next dring index
	 * that has not yet been ack-ed. We send a "start" trigger here
	 * if, and only if, start_cons is true (reset it afterward). Conversely,
	 * vnet_ack() should check if the dring corresponding to cons
	 * is marked READY, but start_cons was false.
	 * If so, vnet_ack() should send out the missed "start" trigger.
	 *
	 * Note that the wmb() above makes sure the cookies et al. are
	 * not globally visible before the VIO_DESC_READY, and that the
	 * stores are ordered correctly by the compiler. The consumer will
	 * not proceed until the VIO_DESC_READY is visible assuring that
	 * the consumer does not observe anything related to descriptors
	 * out of order. The HV trap from the LDC start trigger is the
	 * producer to consumer announcement that work is available to the
	 * consumer
	 */
	if (!port->start_cons)
		goto ldc_start_done; /* previous trigger suffices */

	err = __vnet_tx_trigger(port, dr->cons);
	if (unlikely(err < 0)) {
		netdev_info(dev, "TX trigger error %d\n", err);
		d->hdr.state = VIO_DESC_FREE;
		dev->stats.tx_carrier_errors++;
		goto out_dropped;
	}

ldc_start_done:
	port->start_cons = false;

	dev->stats.tx_packets++;
	dev->stats.tx_bytes += port->tx_bufs[txi].skb->len;

	dr->prod = (dr->prod + 1) & (VNET_TX_RING_SIZE - 1);
	if (unlikely(vnet_tx_dring_avail(dr) < 1)) {
		netif_tx_stop_queue(txq);
		if (vnet_tx_dring_avail(dr) > VNET_TX_WAKEUP_THRESH(dr))
			netif_tx_wake_queue(txq);
	}

	(void)mod_timer(&port->clean_timer, jiffies + VNET_CLEAN_TIMEOUT);
	rcu_read_unlock();

	vnet_free_skbs(freeskbs);

	return NETDEV_TX_OK;

out_dropped:
	if (pending)
		(void)mod_timer(&port->clean_timer,
				jiffies + VNET_CLEAN_TIMEOUT);
	else if (port)
		del_timer(&port->clean_timer);
	if (port)
		rcu_read_unlock();
	if (skb)
		dev_kfree_skb(skb);
	vnet_free_skbs(freeskbs);
	dev->stats.tx_dropped++;
	return NETDEV_TX_OK;
}

static void vnet_tx_timeout(struct net_device *dev)
{
	/* XXX Implement me XXX */
}

static int vnet_open(struct net_device *dev)
{
	netif_carrier_on(dev);
	netif_tx_start_all_queues(dev);

	return 0;
}

static int vnet_close(struct net_device *dev)
{
	netif_tx_stop_all_queues(dev);
	netif_carrier_off(dev);

	return 0;
}

static struct vnet_mcast_entry *__vnet_mc_find(struct vnet *vp, u8 *addr)
{
	struct vnet_mcast_entry *m;

	for (m = vp->mcast_list; m; m = m->next) {
		if (ether_addr_equal(m->addr, addr))
			return m;
	}
	return NULL;
}

static void __update_mc_list(struct vnet *vp, struct net_device *dev)
{
	struct netdev_hw_addr *ha;

	netdev_for_each_mc_addr(ha, dev) {
		struct vnet_mcast_entry *m;

		m = __vnet_mc_find(vp, ha->addr);
		if (m) {
			m->hit = 1;
			continue;
		}

		if (!m) {
			m = kzalloc(sizeof(*m), GFP_ATOMIC);
			if (!m)
				continue;
			memcpy(m->addr, ha->addr, ETH_ALEN);
			m->hit = 1;

			m->next = vp->mcast_list;
			vp->mcast_list = m;
		}
	}
}

static void __send_mc_list(struct vnet *vp, struct vnet_port *port)
{
	struct vio_net_mcast_info info;
	struct vnet_mcast_entry *m, **pp;
	int n_addrs;

	memset(&info, 0, sizeof(info));

	info.tag.type = VIO_TYPE_CTRL;
	info.tag.stype = VIO_SUBTYPE_INFO;
	info.tag.stype_env = VNET_MCAST_INFO;
	info.tag.sid = vio_send_sid(&port->vio);
	info.set = 1;

	n_addrs = 0;
	for (m = vp->mcast_list; m; m = m->next) {
		if (m->sent)
			continue;
		m->sent = 1;
		memcpy(&info.mcast_addr[n_addrs * ETH_ALEN],
		       m->addr, ETH_ALEN);
		if (++n_addrs == VNET_NUM_MCAST) {
			info.count = n_addrs;

			(void) vio_ldc_send(&port->vio, &info,
					    sizeof(info));
			n_addrs = 0;
		}
	}
	if (n_addrs) {
		info.count = n_addrs;
		(void) vio_ldc_send(&port->vio, &info, sizeof(info));
	}

	info.set = 0;

	n_addrs = 0;
	pp = &vp->mcast_list;
	while ((m = *pp) != NULL) {
		if (m->hit) {
			m->hit = 0;
			pp = &m->next;
			continue;
		}

		memcpy(&info.mcast_addr[n_addrs * ETH_ALEN],
		       m->addr, ETH_ALEN);
		if (++n_addrs == VNET_NUM_MCAST) {
			info.count = n_addrs;
			(void) vio_ldc_send(&port->vio, &info,
					    sizeof(info));
			n_addrs = 0;
		}

		*pp = m->next;
		kfree(m);
	}
	if (n_addrs) {
		info.count = n_addrs;
		(void) vio_ldc_send(&port->vio, &info, sizeof(info));
	}
}

static void vnet_set_rx_mode(struct net_device *dev)
{
	struct vnet *vp = netdev_priv(dev);
	struct vnet_port *port;

	rcu_read_lock();
	list_for_each_entry_rcu(port, &vp->port_list, list) {

		if (port->switch_port) {
			__update_mc_list(vp, dev);
			__send_mc_list(vp, port);
			break;
		}
	}
	rcu_read_unlock();
}

static int vnet_change_mtu(struct net_device *dev, int new_mtu)
{
	if (new_mtu < 68 || new_mtu > 65535)
		return -EINVAL;

	dev->mtu = new_mtu;
	return 0;
}

static int vnet_set_mac_addr(struct net_device *dev, void *p)
{
	return -EINVAL;
}

static void vnet_get_drvinfo(struct net_device *dev,
			     struct ethtool_drvinfo *info)
{
	strlcpy(info->driver, DRV_MODULE_NAME, sizeof(info->driver));
	strlcpy(info->version, DRV_MODULE_VERSION, sizeof(info->version));
}

static u32 vnet_get_msglevel(struct net_device *dev)
{
	struct vnet *vp = netdev_priv(dev);
	return vp->msg_enable;
}

static void vnet_set_msglevel(struct net_device *dev, u32 value)
{
	struct vnet *vp = netdev_priv(dev);
	vp->msg_enable = value;
}

static const struct ethtool_ops vnet_ethtool_ops = {
	.get_drvinfo		= vnet_get_drvinfo,
	.get_msglevel		= vnet_get_msglevel,
	.set_msglevel		= vnet_set_msglevel,
	.get_link		= ethtool_op_get_link,
};

static void vnet_port_free_tx_bufs(struct vnet_port *port)
{
	struct vio_dring_state *dr;
	int i;

	dr = &port->vio.drings[VIO_DRIVER_TX_RING];
	if (dr->base) {
		ldc_free_exp_dring(port->vio.lp, dr->base,
				   (dr->entry_size * dr->num_entries),
				   dr->cookies, dr->ncookies);
		dr->base = NULL;
		dr->entry_size = 0;
		dr->num_entries = 0;
		dr->pending = 0;
		dr->ncookies = 0;
	}

	for (i = 0; i < VNET_TX_RING_SIZE; i++) {
		struct vio_net_desc *d;
		void *skb = port->tx_bufs[i].skb;

		if (!skb)
			continue;

		d = vio_dring_entry(dr, i);
		if (d->hdr.state == VIO_DESC_READY)
			pr_warn("active transmit buffers freed\n");

		ldc_unmap(port->vio.lp,
			  port->tx_bufs[i].cookies,
			  port->tx_bufs[i].ncookies);
		dev_kfree_skb(skb);
		port->tx_bufs[i].skb = NULL;
		d->hdr.state = VIO_DESC_FREE;
	}
}

static int vnet_port_alloc_tx_ring(struct vnet_port *port)
{
	struct vio_dring_state *dr;
	unsigned long len, elen;
	int i, err, ncookies;
	void *dring;

	dr = &port->vio.drings[VIO_DRIVER_TX_RING];

	elen = sizeof(struct vio_net_desc) +
	       sizeof(struct ldc_trans_cookie) * 2;
	if (vio_version_after_eq(&port->vio, 1, 7))
		elen += sizeof(struct vio_net_dext);
	len = VNET_TX_RING_SIZE * elen;

	ncookies = VIO_MAX_RING_COOKIES;
	dring = ldc_alloc_exp_dring(port->vio.lp, len,
				    dr->cookies, &ncookies,
				    (LDC_MAP_SHADOW |
				     LDC_MAP_DIRECT |
				     LDC_MAP_RW));
	if (IS_ERR(dring)) {
		err = PTR_ERR(dring);
		goto err_out;
	}

	dr->base = dring;
	dr->entry_size = elen;
	dr->num_entries = VNET_TX_RING_SIZE;
	dr->prod = dr->cons = 0;
	port->start_cons  = true; /* need an initial trigger */
	dr->pending = VNET_TX_RING_SIZE;
	dr->ncookies = ncookies;

	for (i = 0; i < VNET_TX_RING_SIZE; ++i) {
		struct vio_net_desc *d;

		d = vio_dring_entry(dr, i);
		d->hdr.state = VIO_DESC_FREE;
	}
	return 0;

err_out:
	vnet_port_free_tx_bufs(port);

	return err;
}

#ifdef CONFIG_NET_POLL_CONTROLLER
static void vnet_poll_controller(struct net_device *dev)
{
	struct vnet *vp = netdev_priv(dev);
	struct vnet_port *port;
	unsigned long flags;

	spin_lock_irqsave(&vp->lock, flags);
	if (!list_empty(&vp->port_list)) {
		port = list_entry(vp->port_list.next, struct vnet_port, list);
		napi_schedule(&port->napi);
	}
	spin_unlock_irqrestore(&vp->lock, flags);
}
#endif
static LIST_HEAD(vnet_list);
static DEFINE_MUTEX(vnet_list_mutex);

static const struct net_device_ops vnet_ops = {
	.ndo_open		= vnet_open,
	.ndo_stop		= vnet_close,
	.ndo_set_rx_mode	= vnet_set_rx_mode,
	.ndo_set_mac_address	= vnet_set_mac_addr,
	.ndo_validate_addr	= eth_validate_addr,
	.ndo_tx_timeout		= vnet_tx_timeout,
	.ndo_change_mtu		= vnet_change_mtu,
	.ndo_start_xmit		= vnet_start_xmit,
	.ndo_select_queue	= vnet_select_queue,
#ifdef CONFIG_NET_POLL_CONTROLLER
	.ndo_poll_controller	= vnet_poll_controller,
#endif
};

static struct vnet *vnet_new(const u64 *local_mac)
{
	struct net_device *dev;
	struct vnet *vp;
	int err, i;

	dev = alloc_etherdev_mqs(sizeof(*vp), VNET_MAX_TXQS, 1);
	if (!dev)
		return ERR_PTR(-ENOMEM);
	dev->needed_headroom = VNET_PACKET_SKIP + 8;
	dev->needed_tailroom = 8;

	for (i = 0; i < ETH_ALEN; i++)
		dev->dev_addr[i] = (*local_mac >> (5 - i) * 8) & 0xff;

	vp = netdev_priv(dev);

	spin_lock_init(&vp->lock);
	vp->dev = dev;

	INIT_LIST_HEAD(&vp->port_list);
	for (i = 0; i < VNET_PORT_HASH_SIZE; i++)
		INIT_HLIST_HEAD(&vp->port_hash[i]);
	INIT_LIST_HEAD(&vp->list);
	vp->local_mac = *local_mac;

	dev->netdev_ops = &vnet_ops;
	dev->ethtool_ops = &vnet_ethtool_ops;
	dev->watchdog_timeo = VNET_TX_TIMEOUT;

	dev->hw_features = NETIF_F_TSO | NETIF_F_GSO | NETIF_F_GSO_SOFTWARE |
			   NETIF_F_HW_CSUM | NETIF_F_SG;
	dev->features = dev->hw_features;

	err = register_netdev(dev);
	if (err) {
		pr_err("Cannot register net device, aborting\n");
		goto err_out_free_dev;
	}

	netdev_info(dev, "Sun LDOM vnet %pM\n", dev->dev_addr);

	list_add(&vp->list, &vnet_list);

	return vp;

err_out_free_dev:
	free_netdev(dev);

	return ERR_PTR(err);
}

static struct vnet *vnet_find_or_create(const u64 *local_mac)
{
	struct vnet *iter, *vp;

	mutex_lock(&vnet_list_mutex);
	vp = NULL;
	list_for_each_entry(iter, &vnet_list, list) {
		if (iter->local_mac == *local_mac) {
			vp = iter;
			break;
		}
	}
	if (!vp)
		vp = vnet_new(local_mac);
	mutex_unlock(&vnet_list_mutex);

	return vp;
}

static void vnet_cleanup(void)
{
	struct vnet *vp;
	struct net_device *dev;

	mutex_lock(&vnet_list_mutex);
	while (!list_empty(&vnet_list)) {
		vp = list_first_entry(&vnet_list, struct vnet, list);
		list_del(&vp->list);
		dev = vp->dev;
		/* vio_unregister_driver() should have cleaned up port_list */
		BUG_ON(!list_empty(&vp->port_list));
		unregister_netdev(dev);
		free_netdev(dev);
	}
	mutex_unlock(&vnet_list_mutex);
}

static const char *local_mac_prop = "local-mac-address";

static struct vnet *vnet_find_parent(struct mdesc_handle *hp,
						u64 port_node)
{
	const u64 *local_mac = NULL;
	u64 a;

	mdesc_for_each_arc(a, hp, port_node, MDESC_ARC_TYPE_BACK) {
		u64 target = mdesc_arc_target(hp, a);
		const char *name;

		name = mdesc_get_property(hp, target, "name", NULL);
		if (!name || strcmp(name, "network"))
			continue;

		local_mac = mdesc_get_property(hp, target,
					       local_mac_prop, NULL);
		if (local_mac)
			break;
	}
	if (!local_mac)
		return ERR_PTR(-ENODEV);

	return vnet_find_or_create(local_mac);
}

static struct ldc_channel_config vnet_ldc_cfg = {
	.event		= vnet_event,
	.mtu		= 64,
	.mode		= LDC_MODE_UNRELIABLE,
};

static struct vio_driver_ops vnet_vio_ops = {
	.send_attr		= vnet_send_attr,
	.handle_attr		= vnet_handle_attr,
	.handshake_complete	= vnet_handshake_complete,
};

static void print_version(void)
{
	printk_once(KERN_INFO "%s", version);
}

const char *remote_macaddr_prop = "remote-mac-address";

static void
vnet_port_add_txq(struct vnet_port *port)
{
	struct vnet *vp = port->vp;
	int n;

	n = vp->nports++;
	n = n & (VNET_MAX_TXQS - 1);
	port->q_index = n;
	netif_tx_wake_queue(netdev_get_tx_queue(vp->dev, port->q_index));
}

static void
vnet_port_rm_txq(struct vnet_port *port)
{
	port->vp->nports--;
	netif_tx_stop_queue(netdev_get_tx_queue(port->vp->dev, port->q_index));
}

static int vnet_port_probe(struct vio_dev *vdev, const struct vio_device_id *id)
{
	struct mdesc_handle *hp;
	struct vnet_port *port;
	unsigned long flags;
	struct vnet *vp;
	const u64 *rmac;
	int len, i, err, switch_port;

	print_version();

	hp = mdesc_grab();

	vp = vnet_find_parent(hp, vdev->mp);
	if (IS_ERR(vp)) {
		pr_err("Cannot find port parent vnet\n");
		err = PTR_ERR(vp);
		goto err_out_put_mdesc;
	}

	rmac = mdesc_get_property(hp, vdev->mp, remote_macaddr_prop, &len);
	err = -ENODEV;
	if (!rmac) {
		pr_err("Port lacks %s property\n", remote_macaddr_prop);
		goto err_out_put_mdesc;
	}

	port = kzalloc(sizeof(*port), GFP_KERNEL);
	err = -ENOMEM;
	if (!port)
		goto err_out_put_mdesc;

	for (i = 0; i < ETH_ALEN; i++)
		port->raddr[i] = (*rmac >> (5 - i) * 8) & 0xff;

	port->vp = vp;

	err = vio_driver_init(&port->vio, vdev, VDEV_NETWORK,
			      vnet_versions, ARRAY_SIZE(vnet_versions),
			      &vnet_vio_ops, vp->dev->name);
	if (err)
		goto err_out_free_port;

	err = vio_ldc_alloc(&port->vio, &vnet_ldc_cfg, port);
	if (err)
		goto err_out_free_port;

	netif_napi_add(port->vp->dev, &port->napi, vnet_poll, NAPI_POLL_WEIGHT);

	INIT_HLIST_NODE(&port->hash);
	INIT_LIST_HEAD(&port->list);

	switch_port = 0;
	if (mdesc_get_property(hp, vdev->mp, "switch-port", NULL) != NULL)
		switch_port = 1;
	port->switch_port = switch_port;
	port->tso = true;
	port->tsolen = 0;

	spin_lock_irqsave(&vp->lock, flags);
	if (switch_port)
		list_add_rcu(&port->list, &vp->port_list);
	else
		list_add_tail_rcu(&port->list, &vp->port_list);
	hlist_add_head_rcu(&port->hash,
			   &vp->port_hash[vnet_hashfn(port->raddr)]);
	vnet_port_add_txq(port);
	spin_unlock_irqrestore(&vp->lock, flags);

	dev_set_drvdata(&vdev->dev, port);

	pr_info("%s: PORT ( remote-mac %pM%s )\n",
		vp->dev->name, port->raddr, switch_port ? " switch-port" : "");

	setup_timer(&port->clean_timer, vnet_clean_timer_expire,
		    (unsigned long)port);

	napi_enable(&port->napi);
	vio_port_up(&port->vio);

	mdesc_release(hp);

	return 0;

err_out_free_port:
	kfree(port);

err_out_put_mdesc:
	mdesc_release(hp);
	return err;
}

static int vnet_port_remove(struct vio_dev *vdev)
{
	struct vnet_port *port = dev_get_drvdata(&vdev->dev);

	if (port) {

		del_timer_sync(&port->vio.timer);

		napi_disable(&port->napi);

		list_del_rcu(&port->list);
		hlist_del_rcu(&port->hash);

		synchronize_rcu();
		del_timer_sync(&port->clean_timer);
		vnet_port_rm_txq(port);
		netif_napi_del(&port->napi);
		vnet_port_free_tx_bufs(port);
		vio_ldc_free(&port->vio);

		dev_set_drvdata(&vdev->dev, NULL);

		kfree(port);

	}
	return 0;
}

static const struct vio_device_id vnet_port_match[] = {
	{
		.type = "vnet-port",
	},
	{},
};
MODULE_DEVICE_TABLE(vio, vnet_port_match);

static struct vio_driver vnet_port_driver = {
	.id_table	= vnet_port_match,
	.probe		= vnet_port_probe,
	.remove		= vnet_port_remove,
	.name		= "vnet_port",
};

static int __init vnet_init(void)
{
	return vio_register_driver(&vnet_port_driver);
}

static void __exit vnet_exit(void)
{
	vio_unregister_driver(&vnet_port_driver);
	vnet_cleanup();
}

module_init(vnet_init);
module_exit(vnet_exit);